ORA-03115: unsupported network datatype or representation?

I'm using Java 1.5, Tomcat, and Oracle 10g XE.  The following code gives me an ORA-03115 error:

      public boolean updateModuleScore(int sessID, int module, int score)
            {
               boolean success = false;

               String sql =
                  "UPDATE MODULERESULTS " +
                  "SET COMPLETIONDATE=SYSDATE,SCORE=? " +
                  "WHERE SESSIONID=? AND MODULE=?";

               PreparedStatement pst = null ;
               Connection con = null;

            try
            {
                  con = DBConnect.getConnection();

                  pst = con.prepareStatement(sql);
                  pst.setInt(1,score);
                  pst.setInt(2,sessID);
                  pst.setInt(3,module);

                  System.out.println("executeQuery");
                  pst.executeQuery(sql);
                  System.out.println("executeQuery done");

                  success = true ;
                  System.out.println("Updated Module ModuleResults");
            }
            catch (SQLException e)
            {
                success = false ;
                  System.out.println(e.getMessage());
                  setError(e);
            }

            finally
            {
                  close(con,pst);
            }

            return success;
      }

The exception occurs on the executeQuery() statement.

The table is defined as follows:

SESSIONID NUMBER(9,0)
MODULE NUMBER(3,0)
COMPLETIONDATE DATE
SCORE NUMBER(3,0)

We're using pooled connections thorugh JNDI.  When I downloaded a different version of ojdbc14.jar from the Oracle site to see if that fixed this problem, the pooled connections no longer worked.  Apparently there are several different versions of ojdbc14.jar, all with different file sizes, but I can't figure out how to tell the difference between them.

Please help!!!